Presentation on theme: "By: Jasmine Ahmed, Shelley Bi, Christina Bai"— Presentation transcript:
1By: Jasmine Ahmed, Shelley Bi, Christina Bai Free FallBy: Jasmine Ahmed, Shelley Bi, Christina Bai
2What is Free Fall?Free fall is the motion of an object falling with a constant accelerationIn this case, the constant acceleration would be a = g = 9.81 m/s2, but since objects free fall towards the Earth's surface ---> a = - g = m/s2 When there is no air resistance, all objects fall with the same acceleration regardless of their masses
3For Example . . .If an astronaut dropped a hammer and a feather in space, the hammer and the feather would fall towards the surface with the same acceleration, therefore they would land on the surface at the exact same time.
4In free fall, the acceleration, 9. 81 m/s2, remains constant In free fall, the acceleration, 9.81 m/s2, remains constant. This occurs, because of the gravity near the Earth's surface. V = at
5To find the distance traveled by an object during free fall, we use the formula, where a=g d= vit + 1/2 at2When an object starts at rest, the formula is reduced to d= 1/2 at2, because the velocity is 0 m/s.
6Problem 1A ball dropped from rest falls freely until it hits the ground with a speed of 20 meters per second. The time during which the ball is in free fall is approximately (1) 1 s (2) 2 s(3) 0.5 s(4) 10 s
7Solution to Problem 1 V = at t = V a t = 20 m/s -9.81 m/s^2 (2) t = 2 seconds
8Problem 2An object is allowed to fall freely near the surface of a planet. The object has an acceleration due to gravity of 24 m/s2 How far will the object fall during the first second? (1) 24 meters (3) 9.8 meters (2) 12 meters (4) 4.9 meters
9d= 1/2 at2 d= 1/2 (24 m/s2)(1s) (2) d= 12 m Solution to Problem 2d= 1/2 at2 d= 1/2 (24 m/s2)(1s) (2) d= 12 m
10Problem 33. Starting from rest, object A falls freely for 2.0 seconds, and object B falls freely for 4.0 seconds. Compared with object A, object B falls (1) one-half as far (3) three times as far (2) twice as far (4) four times as far
11Solution to Problem 3 d= 1/2 at2 d= 1/2(-9.81m/s2)(2s)2 d= 19.62 m d= m (4) four times as far